This application is directed to a novel method of preparing sulfurized olefins and to lubricant and fuel compositions containing same.
The use of sulfurized olefins has been well-known for their extreme-pressure and antiwear properties when formulated into lubricants, as exemplified by U.S. Pat. No. 3,703,504 (Horodysky).
Sulfurized olefin compositions have been prepared by, for example, the reaction of sulfur, isobutylene, and hydrogen sulfide as exemplified by U.S. Pat. No. 4,344,854 (Davis and Holden).
It has now been found that the reaction of sulfur, olefins, and sodium sulfide hydrates produces a sulfurized olefin mixture with no, or decreased amounts of, dithiolethiones and no halogens. These reaction products possess excellent extreme-pressure and antiwear properties, reduced color, odor, and corrosivity towards copper when compared to sulfurized olefin mixtures produced by direct reaction of an olefin with sulfur, in the absence of sodium sulfide. No other reference suggests the direct sulfurization of olefins with elemental sulfur and alkali metal sulfide.
Exceptional benefits are expected for a variety of synthetic and mineral oil applications from the sulfurized olefins produced in the novel method of this invention. The lubricant compositions disclosed are believed to be novel. It is also likely that the unexpected performance properties of these reaction products may also find use in hydrocarbon and/or alcohol-containing fuel compositions. These compositions to the best of applicants' knowledge and belief have not been previously used as extreme-pressure/antiwear additives in lubricating oils, greases, or fuel applications. Additional benefits include antifatique, antiscoring, friction reducing, thermal stabilizing and antioxidant properties.